NEW SECURITY BUG IN YOSEMITE!
Let me preface... I have 3 copies of Yosemite I'm testing, one basic, one my daily use, one my backup and a clean copy of Mavericks to balance against with all the same settings as my daily use in case I have to revert.
On my daily use YOSEMITE install, the latest update corrupted my System Preferences log-in settings meaning that even though I'm requiring a user name & password, it's automatically logging in against my wishes.
This is a MAJOR security issue and bug!
Oh, on this Yosemite install, it fixed the WRONG SCREEN problem by evading all my boot security settings and will not honor any settings requiring a password while booting.
ONCE AGAIN THIS IS A MAJOR SECURITY FLAW!
Yes, it sort of solved one problem, but created a MUCH BIGGER ONE!
I hate to say this, but I think I'm really going to have to go back to Mavericks.